This invention relates generally to the art of pipe networks for buildings, and especially to apparatus and systems for making pipe networks fire-retardant.
For a number of years, pipe networks which have extended through floors of building have been made fire retardant by encircling pipes with fire-stop intumescent material which expands upon contact with heat to close off the pipes at the floors. It has been suggested to do this by encircling a pipe with a metal container enclosing intumescent material and fastening this metal container to a bottom surface of a floor through which the pipe passes. However, a difficulty with prior-art systems is that the intumescent material must be installed separately from the pipe and normally must be put in place after the pipe has been extended through holes in floors. Thus, it is an object of this invention to provide an under-floor fire-stop coupling, and method of using the same which can be installed at the same time pipe passing through a floor hole is installed. Other suggestions have been made for casting pipe couplings having intumescent collars thereabout into concrete floors when they are poured. Such "cast-in" couplings having intumescent collars works quite well with poured floors, however, many floors are not poured, but rather are constructed of prefabricated concrete slabs laid on floor trusses or other types of supports. Thus, it is an object of this invention to provide a fire-stop coupling which can be used with pre-fabricated concrete slab floors.
Yet another difficulty with prior-art methods of mounting intumescent collars about pipes below floors with metallic containers is that one pipes are extended through holes in floors, the gaps between the pipes and floors must be filled with a hardening substance or concrete. Normally, it is more convenient to fill these spaces before metallic containers with intumescent materials are placed on pipes below floors because water from hardening cement might go into the intumescent material, thereby damaging it, and a rigid holding surface must be used below the floor to hold the filling concrete in place. It is an object of this invention to provide an under-floor fire-stop coupling and method which allows pipe to be extended through a floor with a metallic container fire-stop device thereon prior to filling the gap between the pipe and a hole through which it passes. Further, it is an object of this invention to provide a device which inherently closes the bottom portion of the gap between the pipe and the hole with a rigid surface for supporting wet concrete placed in the gap.
One problem with prior-art fire-stop intumescent material collars is that workmen must form them at job sites, which is inconvenient. It is therefore an object of this invention to provide a pipe coupling assembly with an intumescent collar which can be prepackaged prior to being transported and sold.
It is a further object of this invention to provide a pipe coupling assembly having an intumescent-material collar which is easy and relatively inexpensive to construct, but yet which is durable and effective in responding to heat.